Six men have been given jail sentences of between 10 and 23 years for sexually exploiting five teenage girls, after the biggest prosecution of a Rotherham grooming gang by the National Crime Agency.

A court heard how the group targeted the vulnerable schoolgirls, using drugs and alcohol to rape and sexually assault their victims between 1998 and 2005.

One girl was forced by her parents to have an abortion when she was about 14 after being raped by a group of men in a forest. Another said she had been exploited by “100 Asian men” by the age of 16. The complainants said in statements that the men had “destroyed” them and taken their childhoods away from them.

Sentencing at Sheffield crown court on Friday, judge Sarah Wright said: “Each in your own way perpetrated, facilitated or encouraged the sexual abuse of these young girls. Each of the complainants in this case were groomed, coerced and intimidated. Each of them was groomed. Each of you groomed. You can have been in no doubt that the complainants were vulnerable in the extreme.”

Wright said the defendants had indulged in “cynical manipulation and exploitation of your victims, which showed a maturity well beyond your chronological age”.

Mohammed Imran Ali Akhtar, 37, was described by detectives as the ringleader of the group. One girl told how he would take her to meet taxi drivers so they could abuse her. Another said he raped her in the back of a car.

Akhtar was found guilty of one count of rape, one count of aiding and abetting rape, three counts of indecent assault, one count of procuring a girl under 21 to have unlawful sexual intercourse with another, and one count of sexual assault. He was sentenced to 23 years in jail.

Iqlak Yousaf, 34, was given 20 years for two counts of rape and two counts of indecent assault. Nabeel Kurshid, 35, was found guilty of two counts of rape and one count of indecent assault. He was sentenced to 19 years. Tanweer Ali, 37, was given 14 years for two counts of rape, two counts of indecent assault and one count of false imprisonment.

Salah Ahmed El-Hakam, 39, was found guilty of one count of rape, and sentenced to 15 years. Asif Ali, 33, was found guilty of two counts of indecent assault and sentenced to 10 years. A seventh man, who cannot be named for legal reasons, was convicted of two counts of rape and will be sentenced at a later date.

The trial was the biggest prosecution to date under the National Crime Agency’s Operation Stovewood investigation into child sexual exploitation in the South Yorkshire town.

The £90m inquiry is examining offences committed between 1997 and 2013 and has identified 1,523 potential victims. It is investigating allegations against 426 people, of whom 151 are designated suspects.

So far, 14 people have been convicted under Operation Stovewood. A further 24 suspects have been charged and 68 interviewed under caution. The investigation has recorded 648 grooming crimes over a 16-year period.